Curable mixtures comprising epoxide compositions and divalent tin salts



United States Patent 3,117fifi9 CURABLEZ P/HXTURES EIQMPRESING EPQXHDE OJMPGETZQNS AND DIVALENT Tm SALT William it. Proops, Charleston, and George W. Fowler, South Charleston, W. Va, assignors to Union Carbide @orporation, a c rporation or New York No Drawing. Filed Dec. 24, 1959, Ser. No. $61,748 it Claims. (Cl. 24150-18} This invention relates to epoxide compositions and to the curing of certain epoxides with divalent tin catalysts.

A variety of catalysts have been suggested for use in promoting the cure or polymerization of epoxide compositions into hardened, infusible and insoluble products of relatively high molecular weight, the cured epoxy compound being either in the form of a homopolyrner or copolymer with various organic compounds capable of interaction with the active groups of the epoxide. Included among the known catalysts are strongly acidic materials such as sulfuric acid, phosphoric acid, etc.; aromatic sulfonic acids such as toluenesulfonic acid and benzenesulionic acid; Lewis acids, e.g., boron trifiuoride, stannic chloride, etc; and boron trifluoride-amine complexes such as boron trifiuoride-monoethylamine, boron tritluoridepiperidine, and the like. Although these catalysts are effective for the curing or polymerization process, their use has been handicapped to some extent due to a number of reasons. For example, the use of Lewis acid catalysts such as boron trifiuoride suffer the disadvantage of effecting rapid and uncontrolled exotherms during the cure of epoxides to resins, frequently causing thermal decomposition in the composition as evidenced by charring, or expulsion of components as indicated by bubble formation and foaming. A number of these catalysts are of a corrosive nature and cause uncontrollable gel rates in the cure of certain epoxide formulations which thus seriously limits their industrial application in the field of coatings, adhesives, and potting compositions.

The present invention is based on the discovery that divalent tin compounds selected from the group consisting of stannous acylates and stannous alkoxides are especially eliective catalysts for promoting the cure of epoxide compositions w h contain either a cyclohexene oxide or cyclopentene oxide group. It has been found that the incorporation of stannous acylates or stannous alkoxides in epoxide compounds of the above type provides curable compositions which have a good working life and can be cured at roon temperature Without incurring rapid gelation or uncontrollable exotherrns. The curable compositions can be spread, brushed or sprayed by techniques known in the paint, varnish and lacquer industries, and can be advantageously used in the encapsulation of electrical components. Mixtures of stannous catalysts with epoxides containing the cyclohexene oxide or cyclopentene oxide group offer a distanct advantage over epoxides of the polyglycidyl ether type inasmuch as they can be reacted with various hardeners and foamed by internal development of carbon dioxide or by a blowing agent which vaporizes at or below the temperature of the foaming mass to provide foamed polymers of widely varying and preselected properties. Foamed polymers of this type find wide utility in the field of structural reinforcement and insulation.

The stannous acylates which are used for purposes of the invention are the divalent tin salts of aliphatic monoand dicarboxylic acids which contain from 1 to 54 carbon atoms. The acids can be saturated such as acetic acid, Z-ethylhexanoic, etc., or they may be unsaturated acids such as oleic, linoleic, ricinoleic, and the like.

Examples of specific stannous acylates which can be used include: stannous acetate, stannous propionate, stannous oxalate, stannous tartrate, stannous butyrate, stan- "ice nous valerate, stannous caproate, stannous caprylate, stannous octoate, stannous laurate, stannous palmitate, stannous stearate, and stannous oleate. Of these materials the preferred catalysts are stannous acetate, stannous octoate and stannous oleate.

The stannous compounds which are used may be represented by the formula:

in which R is a monovalent hydrocarbon radical, saturated or unsaturated, branched chain or straight chain, containing 1 to 18 carbon atoms, preferably 3 to 12. Representative examples of stannous allioxides include stannous methoxide, stannous isopropoxide, stannous butoxide, stannous t-butoxide, stannous Z-ethylhexoxide, stannous tridecanoxide, stannous heptadecanoxide, stannous phenoxide, and o, m and p-stannous cresoxides, etc.

Either class of stannous catalysts may be substituted with hydroxy, halo and keto, etc., groups.

In carrying out the invention the stannous catalysts are mixed with epoxidcs to obtain a homogeneous curable composition. With epoxides that are liquid and viscous, the catalyst can be simply admixed with the epoxide by conventional means as, for example, by stirrers and impellers, etc. When the catalyst and epoxide are immiscible at room temperatures, or if the epoxide is normally solid, the epoxide can be melted or mixed with a liquid organic solvent. Typical solvents inc.ude organic ethers such as diethyl ether, methyl propyl ether, etc; organic esters, such as methyl acetate, ethyl propionate, etc.; and organic ketones such as acetone and cyclohexanone, etc.

The amount of catalyst employed will vary with the cure rate desired and the curing temperature employed. As a general guide good results are obtained by utilizing the stannous catalyst in amounts ranging between 0.001 and 20 percent, preferably 0.1 to 10 percent, by weight, based on the total weight of the curable epoxide composition.

The mixture of epoxide composition and catalyst can be cured over a wide temperature range. For example, the catalyst can be added to the epoxide composition at room temperatures, i.e., about 15 to C., and the cure eifected, or if a rapid cure is desired the mixture can be heated to temperatures as high as 250 C. or more. Higher temperatures above 250 C. are generally undesirable due to the discoloration which may be induced. Other single curing temperatures and combinations of curing temperatures can be employed as desired.

The stannous catalysts above described are used to promote the cure of a wide variety of known epoxide compositions which contain either a cyclohexene oxide or cyclopentene oxide group, the cured composition produced being in the form of a homopolymer or copolyrner with an active organic hardener. The curable epoxide compositions can be monomeric or polymeric, saturated or unsaturated, aliphatic, aromatic or heterocyclic, and can be substituted, if desired, with substituents such as hydroxy, halide, alkyl, aryl, carboxyl, etc.

Specific examples of epoxides which can be cured to provide a variety of useful products are those which contain one or more cyclohexene oxide groups, the term cyclohexene oxide referring to the structure:

Among such epoxides are included: aliphatic polyol epoxycyclohexanecarboxylates exemplified by compounds which include 3-rnethyl-1,5-pentanediol bis(3,4-epoxycyclohexanecarboxylate l,5-pentanediol bis 3,4-epoxycyclohexanecarboxylate) Z-methoxyrnethyl-Z,4-dimethyl-1,5-pentanediol bis 3 ,4-

epoxycyclohexanecarboxylate) ethylene glycol bis (3 ,4-epoxycyclohexanecarboxylate) 2,2-diethyl-1,3-propanediol bis(3,4-epoxyyclohexanecarboxylate),

1,6-hexanediol bis 3 ,4-epoxycyclohexanecarboxylate Z-butene- 1 ,4-diol bis 3,4-epoxycyclohexanecarboxylate) 2-butene-l,4-diol bis(3,4-epoxy-6-methylcyclohexanecarboxylate),

1,1,l-trimethylolpropane tris(3,4-epoxycyclohexanecarboxylate),

1,2,3-propanetriol tris(3,4-epoxycyclohexanecarboxylate);

oxyalkylene glycol epoxycyclohexanecarboxylates exemplified by compounds which include dipropylene glycol bis(2-ethylhexyl 4,5-epoxycyclohexane- 1 ,Z-dicarboxylate) diethylene glycol bis(3,4-epoxy-6-rnethylcyclohexanecarboxylate),

triethylene glycol bis(3,4-epoxycyclohexanecarboxylate;

epoxycyclohexylalkyl epoxycyclohexanecarboxylates exemplified by compounds which include 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate,

3,4-epoxy-l-methylcyclohexylmethyl 3,4-epoxy-1-methylcyclohexanecarboxylate,

3,4-epoxy-2-methylcyclohexylmethyl 3,4-epoxy-2-rnetiylcyclohexanecarboxylate,

(l-cl1loro-3,4-epoxycyclohexan-l-yl)methyl l,-chloro-3,4-

epoxycyclohexanecarboxylate,

(1 bromo-3,4-epoxycyclohexan-I-yD-methyl 1-brorno-3,4-

epoxycyclohexanecarboxylate,

(1-chloro-2-methyl-4,S-epoxycyclohexan-l-yl)methyl lchloro-2-methyl-4,5-epoxycyclohexanecarboxylate;

epoxycyclohexylalkyl dicarboxylates exemplified by compounds which include bis(3,4-epoxycyclohexylmethyl) pimelate, bis(3,4-epoxy-6-methylcyclohexylmethyl) maleate, bis(3,4-epoxy-6-methylcyclohexylmethyl) succinate, bis(3,4-epoxcyclohexylmethyl) oxalate, bis(3,4-epoxy-G-methylcyclohexylmethyl) sebacate, bis(3,4-epoxy-o-methylcyclohexylmethyl) adipate;

epoxycyclohexylalkyl phenylenedicarboxylates exemplified compounds which include bis(3,4-epoxycyclohexylmethyl) terephthalate, bis(3,4-epoxy-6-methylcyclohexylmethyl) terephthalate;

epoxycyclohexylalkyl oxyalkylene glycol others exemplilied by compounds which include bis(3,4-epoxy-6-rnethylcyclohexylmethyl) diethylene glycol ether;

sulfonyldialkanol bis(epoxycyclohexanecarboxylates) exemplified by compounds which include 2,2'-sulfonyldiethanol bis(3,4-epoxycyclohexanecarboxlate);

ep xycyclohexanc-1,2-dicarboximides exemplified by compounds which include N,N'-ethylene bis(4,5-epoxycyclohexane-1,2-dicarboximide);

epoxycyclohexylalliyl carbamates exemplified by compounds which include di(3,4-epoxycyclohexylmethyl) 1,3-tolylenedicarbamate;

epoxycyclohexylalkyl acetals exemplified by compounds which include bis(3,4-epoxy-fi-methylcyclohexylmethyl) 3,4-epoxy-6- methylcyclohexanecarboxaldehyde acetal;

and epoxycyclohexyl-substituted spirobi(rnetadioxane) derivatives exemplified by compounds which include 3,9-bis(3,4-epoxycyclohexyl) spirobi(meta-dioxane).

Other epoxide derivatives may be employed, such as vinyl cyclohexene dioxide, vinyl cyclohexene monoxide, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxy-6-methylcyclohexylmethyl 9,10-epoxystearate, l,2-bis(2,3-epoxy-2- methylpropoxy)ethane, and the like.

Other epoxides which can be cured are those which contain one or more cyclopentene oxide groups, the term cyclopentene oxide referring to the structure:

oil

Among such epoxides are included bis(2,3-epoxycyc1opentyl) ether; dicyclopentadiene dioxide; glycidyl 2,3- epoxycyclopentyl ether; 2,3-epoxycyclopentyl Z-methylglycidyl ether; 2,3-epoxycyclopentyl acrylate; 2,3-epoxycyclopentyl cyclopentyl ether; 2,3-epoxycyclopentyl phenyl ether; 2,3-epoxycyclopentyl Z-cyelopentenyl ether; 2,3- epoxycyclopentyl crotonate; allyl 2,3-epoxycyclopentyl ether; 2,3-epoxycyclopentanol; dicyclopentadiene monoxide; and the like.

The epoxides with the stannous catalyst of the type illustrated above can be homopolymerized or copolymerized with an active organic hardener or combination of active organic hardeners. By the term active organic hardener, as used herein, is meant an organic compound which contains two or more groups which are reactive with epoxy groups. The active organic hardeners illus trated hereinafter are employed in a curing amount, that is, an amount which is sufiicient to cause the epoxide sys tem containing the active organic hardener-(s) to become polymerized. The active organic hardeners can also be employed in varying amounts so as to give a wide variety of properties to the cured epoxide system. Typical groups which are reactive with epoxy groups are active hydrogen groups such as hydroxyl groups, carboxyl groups, amino groups, thiol groups, and the like; and isocyanate groups, isothiocyanate groups, halide atoms of acyl halides, and the like. Oxydicarbonyl groups such as those contained by polycarboxylic acid anhydrides are also ac tive with epoxy groups. One oxydicarbonyl group will react with two epoxy groups and, in this connection, polycarboxylic acid anhydrides need only contain one oxydicarbonyl group in order to function as an active organic hardener with the epoxide compositions of this invention. Stated differently, one oxydicarbonyl group of an anh dride is equivalent to two epoxy-reactive groups.

Representative active organic hardeners include polyiunctional amines, polycarboxylic acid, polycarboxylic acid anhydrides, polyols, i.e., polyhydric phenols and poly hydric alcohols, polythiols, polyisocyanates, polythioiso cyanates, polyacyl halides and others. By the term polyfunctional amine, as used herein, is meant an amine hav ing at least two active amino hydrogen atoms which can be on the same nitrogen atom or difierent nitrogen atoms.

Resins having particularly valuable properties can be formed from mixtures containing the epoxide compositions and polyfunctional amines in such relative proportions as provide from 0.2 to 5.0 amino hydrogens of the amine for each epoxy contained by said epoxide composition. It is preferred to form resins from curable mixtures containg the epoxide compositions and polyfunctional amines which provide from 0.3 to 3.0 amino hydrogens for each epoxy group.

Among the polyfunctional amines contemplated as active organic hardeners include the aliphatic amines, aromatic amines, aralky] amines, cycloaliphatic amines, alkaryl amines, aliphatic polyamines including polyalkylene poly-amines, amino-substituted aliphatic alcohols and phenols, polyamides, addition products of polyamines. and low molecular weight epoxides containing oxirane. oxygen linked to vicinal carbon atoms, and others.

Typical aliphatic amines include methylarnine, ethylamine, propylarnine, isopropylamine, butylamine, isobutyls amine, 2-ethylhexyla1nine, 3-propylheptylamine, and the like.

Examples of aromatic amines, aralkyl amines and alkaryl amines include, among others, aniline, o-hydroxyaniline, m-toluidine, 2,3-xylidine, benzylamine, phenethylamine, l-naphthylamine, meta-, ortho-, and paraphenylenediamines, l,4-naphthalenediamine, 3,4-toluenediamine and the like.

Illustrative cycloaliphatic amines include cyclopentylamine, cyclohexylamine, p-menthane-L8-diamine and others.

Among the polyamides, i.e., those having an average molecular Weight range from about 300 to about 10,000, include condensation products of polycarboxylic acids, in particular, hydrocarbon dicarboxylic acids, such as malonic acid, succinic acid, glutaric acid, adipic acid, dilinolenic acid, and the like, with polyamines, particularly diamines, such as ethylenediamine, propylenediamine and the like.

Aliphatic polyarnines include ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, octylenediamine, nonlenediamine, decylenediamine, and the like. Polyalkylene polyamines such as diethylenetriamine, triethylenetetramine, retraethylpentamine, dipropylenetriamine, and the like, are particularly suitable.

The amino-substituted aliphatic alcohols and phenols suitable for use in the present invention are illustrated by 2-aminoethanol, Z-aminopropanol, 3-aminobutanol, 1,3- diamino-Z-propanol, Z-aminophenyl, 4-aminophenyl, 2,3- diaminoxylenol, and the like.

Other illustrations of poly'functional amines are the addition products of polyamines, in particular, diamines and triarnincs and epoxides containing oxirane oxygen linked to vicinal carbon atoms, such as ethylene oxide, propylene oxide, butadiene dioxide, diglycidyl ether, epoxidized soybean oil, epoxidized safiiower oil, and polyglycidyl polyethers, such as those prepared from polyhydric phenols and epichlorohydrin. Particularly useful polyfunctional amines are the monoand polyhydroxylalkyl polyalkylene and arylene polyamines which can be prepared by the addition reaction of polyalkylene polyamines, arylene polyamines, and the like, e.g., ethylenediamine, propylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, phenylenediamine, methylenedianiline, xylenediamine, and the like, with ethylene oxide or propylene oxide such that the resulting amine adduct contains two or more active hydrogen atoms attached to either one or more amino nitrogen atoms.

Examples of still other polyfunctional amines suitably adaptable include, among others, heterocyclic nitrogen compounds such as piperazine, 2,5-dimethylpiperazine, and the like; aminoalkyl-stubstituted heterocyclic compounds such as N-(aminopropyl)-morpholine, N-(aminoethyl)morpholine, and the like; amino-substituted heterocyclic nitrogen compounds such as melamine, 2,4-diamino-S-(aminoethyl)pyrimidine, and the like; dimethyiurea, guanidine, p .p' sulionyldianiline, 3,9 bis aminoethyD- spirobimetadioxane, hexahydrobenzamide, and others.

Other polyfunctional amines having a total of at least two active amino hydrogen atoms to the molecule can be employed in the epoxide compositions of this invention. For example, such polyfunctional amines as mixtures of p,p-met ylenedianiline and m-phenylenediamine, or other mixtures of two or more polyfunctional amines can be used.

Another class of active organic hardeners which can be reacted with the epoxide compositions above, are the polycarboxylic acids. By the term polycarboxylic acid, as used herein, is meant a compound or polymer having two or more carboxyl groups to the molecule. Curable mixtures can be formed from the epoxide compositions and polycarboxylic acids, which mixtures can be cured to produce a wide variety of useful products. Valuable resins can be made from mixtures containing such amounts of an epoxide composition and polycarboxylic acid as to provide 0.3 to 1.25 carboxyl groups of the acid for each epoxy group contained by the amount of the epoxide composition. 'It is preferred, however, to make resins from curable mixtures which contain such amounts of polycarboxylic acids and epoxide compositions as to provide 0.3 to 1.0 carboxyl group of the acid for each epoxy groups from the epoxide composition.

Representative polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, alkylsuccinic acids, alkenylsuccinic acids, ethylbutenylsuccinic acid, maleic acid, furnaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, ethylidenemalonic acid, isopropy-lidenemalonic acid, allylmalonic acid, muconic acid, alpha-hydramuconic acid, beta-hydromuconic acid, diglycollic acid, dilactic acid, thiodiglycollic acid, 4-amyl- 2,5-heptadienedioic acid, 3-hexynedioic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-carboxy-Z-methylcyclohexaneacetic acid, phthalic acid, isophthalic acid, terephthalic acid, tetra-hydrophthalic acid, tetrachlorophthalic acid, 1,S-naphthalenedicarboxylic acid, 3-carboxycinnamic acid, 1,2-naphthalenedicarboxylic acid, 1,1,5-pentanetricarboxylic acid, 1,2;4-hexanetricarboxylic acid, 2-propyl, 1,2,4-pentanetricarboxylic acid, 5-octene-3,3,6-tricarboxylic acid, 1,2,3-propanetricarboxylic acid, i,2,4-benzenetricarboxylic acid, 1,3,5- benzenetricarboxylic acid, 3-heXene-2,2,3,4-tetracarboxylic acid, 1,2,3, l-benzenetetracarboxylic acid, 1,2,3,5-benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, polymerized fatty acids derived from natural oils, e.g., linseed oil, tung oil, soybean oil, dehydrated castor oil, etc., including mixtures thereof, which have a molecular weight within the range of 500 to 5900, and the like.

Also, as polycarboxylic acids useful in the polymerizable compositions there are included compounds containing ester groups in addition to two or more carboxy groups which can be termed polycarboxy polyesters of polycarboxylic acids, such as those listed above, or the corresponding anhydrides of said acids, esteriiied with polyhydric alcohols. Stated in other words, by the term polycarboxy polyesters, as used herein, is meant polyesters containing two or more carboxy groups per molecule. These polycarboxy polyesters can be prepared by known condensation procedures, employing mol ratios favoring greater than equivalent amounts of polycarboxylic acid, or anhydride. More specifically, the amount of polycarboxylic acid, or anhydride, employed in the esterification reaction should contain more carboxy groups than are required to react with the hydroxyl groups of the amount of polyhydric reactant.

Polyhydric alcohols which can be employed in preparing these polycarboxy polyesters include dihydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,3- propylene glycol, dipropylene glycols, tripropylene glycols, polyoxyethylene glycols, polyoxypropylene glycols, 1,2- butylene glycol, l,4-butylene glycol, pentane-LS-diol, pentane-2,4-diol, 2,2-dimethyltrimethylene glycol, hexanel,4-diol, hexane-1,5-diol, hexa e-1,6-diol, hexane-2,5-diol, 3-methylpentane-1,S-diol, Z-rnethylpentane-2,5-diol, 3- methylpentane-2,5-diol, 2,2-diethylpropane-1,3-diol, 2,2- diethylhexane-l,3-diol, 2,5-dimethylhexane-2,5-diol, octadecane-l,l2-diol, l-butene-3,4-diol, 2-butene-l,4-diol, 2- butyne-l,4-diol, 2,5-dimethyl-3-hexyne-2,5-diol and the like; trihydric alcohols such as glycerol, trimethylolethane, hexane-1,2,6-triol, l,l,l-trimethylolpropane, and the ethylene oxide and propylene oxide adducts thereof; tetrahydric compounds, such as pentaerythritol, diglycerol, and the like; and higher polyhydric compounds such as pentaglycerol, dip-entaerythritol, polyvinyl alcohols and the like. Additional polyhydric alcohols useful in making poly- '5 carbo:-;y polyesters can be prepared by the reaction of epoxides, e.g., diglycidyl diethers of 2,2-propane bisphenol, an reactive hydrogen-containin organic compounds, e.g., amines, polycarboxylic acids, polyhydric 0.1 to. 2.0, preferably from 9.2 to 1.5, hydroxyl groups of the polyol for each epoxy group contained by the amount of the epoxide composition. By the term polyol, as used herein, is meant an organic compound having at compounds and the like. in forming the polycarboxy least two hydroxyl groups which are alcoholic hydroxyl polyesters it is preferable to use a dihydric, trihydric or groups, phenolic hydroxyl groups, or both alcoholic and tetrahydric aliphatic or oxaaliphatic alcohol. The mol phenolic hydroxyl groups. The epoxide composition and ratios in which the polycarboxyl acid or anhydride can polyol can be mixed in any convenient manner. A prebe reacted with polyhydric alcohols in preparing polyferred method, however, is to mix the polyol and epoxide carboxylic polyesters useful in the compositions are those composition in the liquid state so as to obtain a uniform which provide polyesters having more than one carboxy mixture. In forming this mixture it may be necessary to group per molecule. raise the temperature of the polyol and epoxide corn- Curable mixtures containing the epoxide compositions position to at least the melting point or melting point and polycarboxylic acid anhydrides can also be employed range of the highest melting component. Temperatures to produce resins having diversified and valuable properbelow about 150 C. are preferred so as to avoid possible ties. Particularly valuable resins can be made from mixpremature curing of these curable mixtures. Stirring also tures containing such amounts of polycarboxylic acid aids the formation of a homogeneous mixture. anhydride and epoxide compositions as to provide 0.2 to Representative polyols include ethylene glycol, diethyl- 3.0 carboxy equivalent of the anhydritle for each epoxy ene glycol, polyethylene glycols, propylene glycol, digroup of the epoxide composition. it is preferred, howpropylene glycol, polypropylene glycols, trimethylene ever, to make resins from curable mixtures which contain glycols, butanediols, pentanediols, 12,13-tetracosanediol, such amounts of polycarboxylic acid anhydride and glycerol, polyglycerols, pentaerythritoi, sorbitol, polyvinyl epoxide composition as to provide 0.4 to 2.0 carboxy alcohols, cyclohexanediols, inositol, dihydroxytoluenes, equivalent of anhydride for each epoxy group contained resorcinol, cateehol, bis(4-hydroxyphenyl)-2,2-propane, by the amount of epoxide concentration. bis(4-hydroxyphenyl)-rnethane, and the ethylene and Typical polycarboxylic acid anhydrides include sucpropylene oxide adducts thereof, etc. cinic anhydride, glutaric anhydride, propylsuccinic anhy- The following examples illustrate the best mode now dride, methylbutylsuccinic anhydride, hexylsuccinic contemplated for carrying out the invention. anhydride, heptylsuccinic anhydride, pentenylsuccinic In the following examples the examination or descripanhydride, octenylsuccinic anhydride, nonenylsuccinic tion of the resins were conducted at room temperature, anhydride, alpha, beta-diethylsuccinic anhydride, maleic i.e., about 22 C. Barcol hardness values were deteranhydrlde, chloromaleic anhydride, dichloromaleic anmined by the use or" Barcol lm-pressor GYZI-934-1 at hydride, itaconic anhydride, citraconic anhydride, hexaroom temperature. hydrophthalic anhydride, hexachlorphthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic EXAMPLES 142 anhydrioe tetrachlorphthalic anhyd ide; hexachloroendo- In the fonawing examnles, 153 grams of metnylenetetrahythophthalic anhydiide, otherwise known h 1 1 h 1 th 1 t1 1 1 h as chlorendic anny ride, tetrabromophthalic anhydride, met ycyco y .epoxy me 1y Cyco exam carboxylate was mixed with siannous octoate catalyst and tetraiodophthalic anhydride; phthalrc anhydride, 4-nitroq I Hi h rda or E t f E a l 1,1 phthalic anhydride, 1,2-naphthalic anhydride; polymeric r as I 0 ga C a xciep O Xump e e catalyst was added to each system in an amount rangdicarboxylic acid anhydrides, or mixed polymeric dicarmg between 0 .7 to 1.0 percent by W1l1l based on the boxylic acid anhydrides such as those prepared by the t t 1 t A tr 1 a d autocondensation of dicarboxylic acids, for example, 0 a l ha 9 1? wt i was ma eofcr adipic acid, pimelic acid, sebacic acid, hexahydroisofi T i afghan! at 120 160 phthalic acid, terephthalic acid, isophthalic acid, and the f psFlod Bf time mdlcated Table I WwHCh like. Also, other dicarboxylic acid anhydrides, useful in time gelatwn generally Occurred As shown iable 1! our polymerizable compositions include the Diels-Alde the stannous octoate catalyst effectively promotes the aladducts of maleic acid and alicyclic compounds having 'coholic-elloliidfi, P n li hydroxyl-epoxide, carboxylic conjugated double bonds, e.g., methylbicyclo-[2.2.1]hepacidepoxide, acid anhydride-epoxide, isocyanate-epoxide, tene-2,3-dicarboxylic anhydride. and epoxide homopolymerization reaction. In ever in- Thermoset resins can be prepared from mixtures constance Where stannous octoate was used the gel time was taining the epoxide compositions and polyols by providing decreased and/ or the resulting products more resinous.

Table 1 G01 Time Cure Example Organic Hardener Grams Ratio v Resin Description Hrs O. Hrs. C.

Hexanetriol 0.23 0.5 ,g gg 501m: Slight-1y Control 0.23 0.5 2 }Ambcr, viscous liquid. Bisplicnol A 0.64 0. 5 7.5 160 10.5 Amber, brittle. Control 0. 04 0.5 13-1215 160 19.5 160 Do. Nllfllblgfigdlaglc an- 0.9 1.0 0. 75 g }-Ycllow, tough, Barcol 55. Coriizrolul 0.9 1.0 8 5 120 }Yellow, tough, Barcol 54. 'lolu etno diisoey- 0.0 1 0 2.5 120 -3 }Ambcr,brittl0. G iiiio i 0.9 1.0 7.5 120 Do. Scbacic acid 1.0 0.5 0.1 120 }Ycu0w, tough, 13211100114. 00111710 1.0 0.5 2.0 120 }Yellow, tough, Bare0112, Stanncus oet0ate 0.07 v 4. 6 14 P2110 amber, brittle. Contr 14 160 Slightly viscous liquid.

@ Weight percent.

groups per one epoxide group. -2,3-dicarboxylic enhydride,

EXAMPLES 13-18 in the following examples, various epoxides were admixed in the proportions indicated with a hardener systern consisting of a polyol and polycarboxyhc acid an- 10 octoate catalysts were obtained in comparison to those compositions containing the boron trifiuoride-rnonoethylamine catalysts. The resins based on the conventional BF -monoethylainine complex were pitted on the bottom hydride. The temperature of these mixtures was main- 5 indicating Possible confpmibmty Problems and were PitPed tained at about 22 to 28 C. until a cured or partially in amount Proportional to the Catalyst ccncemfatlon cured resin was obtained. The results are shown below USfidresin flaws were 110ml when Simmons Catalysis in Tabie were employed.

Table 11 Example Epoxide Grams Organic Hordcner Grams Catalyst Grams Percent Resin Description 13 senseless-e: 3:: t on 4 22 3:1 Summonsoctoate 0.45 1.3 Resinous in one day.

22 {lltlistgltilifggneg it W PM We 4 days- 16 (to g2 }Stonn0us octoate 0.45 1.3 Thlckened after one day 17 Diglyci y et e 0 61 {M Q Y O N c Rcrnained liquid after 6 days.

Bisphenol A. 133 l 18 "do 52 5 {Hexalletriol 4 }Stsnnous oetoate 0.8 1.0 Tack free on top after 6 days.

EXAMPLES 19 T able IV In the following examples 7.55 grams of 3,4-epoxy-6- Impact rnethylcyclohexylmethyl 3,4-epoxy-S-methylcyclohexane- Catalyst -i Percent carboxylate were mixed with 7.45 grams of polymerized BFHVIEA Sn Octoate fatty acids 1 in the proportions of 0.5 carboxyl group per one epoxide group. Stannous catalysts were then added 8 28 to the mixture in the amounts indicated below Table g 262 ill. Gel times were observed at 60 C. with all resins 4 5 being cured for the total of from 1 to 13 hours at 160 C. 8 26 As shown below, the eiiectiveness of the stannous catalysts provide a short gel time as compared to the non-catalyzed EXAMPLES 26-31 control. The catalyzed systems also demonstrated a grams of 34 pOXy 6 methy1cyclohexylmethyl hard and more -P 3 cured resinepoxy--rnethylcyclohexanecarboxylate were mixed with 7.45 grams of trimer acid used in Examples 19 to 2-5 in bl 111 the proportion of one epoxide group per 0.5 carboxyl group. The various catalysts, as shown in the table below, were then added to the mixture in such an amount Example cmlyit Wtqgfi 35 at Rcsm Description as to provide about 0.3 of one percent as tin based on No 100 (3., the weight of epoxide and acid. As shown below 111 Taole V, the effectiveness of the catalysts is reflected in the coresponding resin gel times at 160 C. as compared to o. 5H0 33 Barccl control containing no catalyst. Also when a poor cat- Stanncus acetate 0. 020 30 Rigid. alyst, or no catalyst, was used, the rate of curing was slow 885g 28 33?" as is indicated by the resin description after curing for a Stamens 0ctoat-c 0.1.5 15 Bigi(l1,l3arco1 total of 13 hours at 160 C. 2; Stannousolcatc.-- 0. 2e 12 Rilgoidishnrcol bl V 25 Staunous iZ-ethyl- 0.12 8 Rigid, Barcol hcmxide- Example Gel time Resin No. Catalyst Wt., g. at160 0., Description 1 Emery 31625 trirner acid, 900 moi. wt.: acid value 183-188; Saponifieotion vcluc=l02 l9S; Specific gravity=0950 at 29 C.

B The catalyst concentration was about 0.3 percent as tin. 25 None W 55430 Flexible Barcol 27 Stannous 0ctoatc 0.15 15 Rigoi di Barcol The following data illustrates the comparison between 28 105120 23 Bmol stannous acylate catalysts and boron trifiuorideamine 20 Dibutyltih (11(2- 0.20 so 150. commexes etliylhexoate).

30 Dibutyltin 0.24 80 D0.

5.75 grams of 3,4-epoxy-6-methylcyclohexylmethyl 3,4- dilaurate.

epoxy-S-methylcyclohexanecarboxylate were mixed with 31 gl g f 3H0 9.25 grams of t-rirner acid used in Examples 19 to 25 in mhe proportion of one epoxide group carboxyl a The catalyst concentration was about 0.3 percent as tin.

group. Stannous octoate and boron trn'iuoride-rnono- EXAMPLE 32 41 ethylarnine, in the amounts indicated below, were then added an the resulting mixtures gelled at 120 C. After Methyl nadic anhydride methylbicyclo-[2.2.l]heptanegelling the mixtures were post cured for 5.5 to 6.8 hours 2,3-dicarboxylic anhydride) was reacted with a variety of at 120 C. plus 6 hours at 160 C. The resulting cured diand triexpoxides using stannous octoate as a catalyst resins were about inch in thickness and about 2% and a series of controls run without the stannous octoate. inches in diameter. These resin plaques were tes.ed with The methyl nadic anhydride 0.9 g.) was placed in a test a (in lont Parlin Impact Tester for impact strength and tube to which was added enough of the desired epoxide the results reported in inch pounds. As shown in Table so that the ratio of epox-ide to carboxyl groups was 1:1. 1V high impact strength of the resins containing stannous About 2 percent stannous octoate (0.6 percent tin) Was 12 minutes, the time being measured from the instant all ingredients were blended together. A rigid foam having a density of 2.6 pounds per cubic foot was obtained. In Example 43, using the diglycidyl ether of bis(4 hydrox y- Table VI Stannous Description of Resin Example Name Wt., g. n Octoate, Mins. at

N o. g. 120

Barcol Remarks Bisgfi-epoxycyclopentyl) 0.91 036 35, 40 Strong tough resin.

e' er. do 0. 91 Viscous liquid.

Vinyl eyclohexene dio. :ide. 0. 7 0. 032 Strong tough resin. do 0.7 Robbery gelno strength. Dicyclopentadiene dioxide- 0. 82 0 034 Too weak Weak brittle resin. do O. 82 Robbery soft gel.

Bis(3,4-epoxy-fi-rnethyl- 2.2 O 052 38 Strong tough rcsin.

cyclohexyl methyl) adipate. 39 do 2.2 T00 soft Do. 40 1,2,3-pr0panotriol tris(3,4- 1. 8 0. 058 T5 40; 45 Soft tough resin.

epoxycyelohexanc earhoxylatc) 41 do 1. 8 45 Strong tough resin.

A Each charge contains 0.9 g. methyl nadir: anhydride plus the amount of epoxide necessary for the epoxide to carboxyl ratio to be 1:1.

b Used about 2 weight percent (0.6 percent based on tin).

v Viscous but not gelled after 195 mins. at 12 C.

* At room temperature, after 195 mins. at C. plus 6 hours at C.

EXAMPLES 42-44 phenyl) propane, the materials were mixed for 4 minutes 1 d a rise of only one inch in 15 minutes noted. After The utility of stannous catalysts with epoxides of the to cyclohexene oxide type compared to glycidyl epoxides no bemg placed m an oven heated to 70 for one hour was demonstrated in the preoaration of rigid epoxide a total rise of inches was Obtained but ocfoams E following procedum curred after cooling to room temperature. A viscous Stannous octoate was dissolved in a half-acid ester q y material was Obtained Using fhe diglycidyl ether prepared by reacting the propylene oxide adduct of gly- 0i p 'h P f P P agam Example 44, carol (molecular Weight 266) with excess maelic am 3f the ingredients were maxed and allowed to stand at room hydride. A solution of the appropriate epoxide, tolylene temperature (Wemlght- The rise Obsfifved Was about an diisocyanate (20% 2,6- and 80% 2,4-isoiners), tr-ichloroinch and the mass viscous foamy q The specific fluoromethane (Ucon 11) and a silicone oil surfactant formulations used in Examples 4244 are shown below (siloxane-oxyalkylene copolymer) was prepared and in Table VI-I.

u Foams made using ratio of epoxido:COOH:NCO equivalents of 1:0.3:0.2, 1 percent stannous octoate, 13 percent Ucon11 and 1 percent X-520 (based on total weight of foam).

b 3,4-epoxy-6anethylcyclohexylmethyl 3,4-epcry-6-methyleyclohexanecarboxylate. Diglycidyl other of bis(4-hydroxyphenyl)propane. d Hali-acid ester prepared by reacting the propylene oxide adduct of glycerol {moL wt. 266) with excess malcic anhydride. mixed into the catalyst-adduct solution. All materials were at a temperature of 28 C. before mixing.

In Example 42, using 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarhoxylate, the ingredients were mixed for 2 minutes, foaming was noticed in 3.5 minutes and rise was complete (7.5 inches) in 10 EXAMPLES 45-46 The utility of stannous catalysts was further demonstrated by the preparation 'of resin summarized in Table 60 VIII below. Using polymerized fatty acids as the organic hardener, the resin prepared from the diglycidyl ether of Table VIII COMPARISON OF EPOXIDES IN RESIN PREPARATIONS a a Used 0.15 g. stannous octotite (1.0 pereent=0.3 percent as tin) in both examples. b Diglyeidyl ether of bis(4-hydroxyphenyl)propane.

c 3,4-9poxy-6-methylcyelohcxyhnethyl 3,4-ep0xy-G-mcthylcyelohexanc cnrboxylatc. d Emery 3102s trimcr acid of Examples 19-25.

13 bis(4-hydroxyphenyl)propane was sticky and gum-my on the bottom, illustrating the incompatibility of the materials. However, with resins prepared from ep oxides containing the cyclohexene oxide structure, all materials were compatible and a hard resin Was obtained.

What is claimed is:

l. A curable mixture comprising (1) an epoxide compound selected from the group consisting of epoxidized dicyclopentadiene, an alkylene di(epoxycyclohexanecarboxylate), an apoxycyclohexylalkyl epoxycyclohexanecarboxylate, epoxycyclohexylmethyl aliphatic dicarboxylates, and epoxycyclohexylalkyl phenylenedicarboxylates, and (2) a divalent tin compound selected from the group consisting of divalent tin salts of aliphatic monoand dicarboxylic acids containing up to 54 carbon atoms.

2. A curable mixture comprising epoxidized dicyclopentadiene and a stannous salt of theformula Sn(O( iR) wherein R is aliphatic hydrocarbon having 2 to 18 carbon atoms.

3. A curable mixture comprising an alkylene bis(epoxycyclohexanecarboxylate) and a stannous salt of the formula 0 smoii-R); wherein R is aliphatic hydrocarbon having 2 to 18 carbon atoms.

4. A curable mixture comprising an epoxycyclohexylalkyl epoxycyclohexanecarboxylate and a stannous salt of the formula 0 Sn(Oi JR)2 wherein R is aliphatic hydrocarbon having 2 to 18 carbons.

5. A curable mixture comprising an epoxycyclohexylmethyl aliphatic dicarboxylate and a stannous salt of the formula Su(0 i l-Rh wherein R is aliphatic hydrocarbon having 2 to 18 carbon atoms.

6. A curable mixture comprising an epoxycyclohexylalkyl phenylenedicarboxylate and a stannous salt of the formula smo -Rh wherein R is aliphatic hydrocarbon having 2 to 18 carbons.

'7. A curable mixture comprising (1) an epoxide compound selected from the group consisting of epoxidized dicyclopentadiene, an alkylene di(epoxyeyclohexanecarboxylate), an epoxycyclohexylalkyl epoxycyclohexanecarboxylate, epoxycyclohexylmethyl aliphatic diearboxylates, and epoxycyclohexylalkyl phenylenedicarboxylates, (2) a divalent tin compound selected from the group consisting of divalent tin salts of aliphatic monoand dicarboxylic acids containing up to 54 carbon atoms, and (3) a curing amount of an organic hardener selected from the group consisting of polyfunctional amines, polycarboxylic acids, polycarboxylic acid anhydrides, polyhydric phenols, polyhydric alcohols, polythiols, polyisocyanates, polythioisocyanates and mixtures of the aforementioned hardeners.

8. A curable mixture comprising 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate and a divalent tin compound selected from the group consisting of divalent tin salts of aliphatic monoand dicarboxylic acids containing up to 54 carbon atoms.

9. A curable mixture comprising bis(3,4-epoxy-6- methycyclohexylmethyl)adipate and a divalent tin compound selected from the group consisting of divalent tin salts of aliphatic monoand dicarboxylic acids containing up to 5 4 carbon atoms.

10. A resin forming process comprising contacting an epoxide compound selected from the group consisting of epoxidized dicyclopentadiene, an alkylene di(epoxycyclohexanecarboxylate), an epoxycyclohexylalkyl epoxycyclohexane carboxylate, epoxycyclohexylmethyl aliphatic dicarboxylates, and epoxycyclohexylalkyl phenylenedicarboxylates, with a divalent tin compound selected from the group consisting of divalent tin salts of aliphatic monoand dicarboxylic acids containing up to 54 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,767,158 Schlenker et al Oct. 16, 1956 2,801,228 Stark et al July 30, 1957 2,935,488 Phillips et al May 3, 1960 

1. A CURABLE MIXTURE COMPRISING (1) AN EPOXIDE COMPOUND SELECTED FROM THE GROUP CONSISTING OF EPOXIDIZED DICYCLOPENTADIENE, AN ALKYLENE DI(EPOXYCYCLOHEXANECARBOXYLATE), AN APOXYCYCLOHEXYLALKYL EPOXYCYCLOHEXANECARBOXYLATE, EPOXYCYCLOHEXYLMETHYL ALIPHATIC DICARBOXYLATES, AND EPOXYCYCLOHEXYLALKYL PHENYLENEDICARBOXYLATES, AND (2) A DIVALENT TIN COMPOUND SELECTED FROM THE GROUP CONSISTING OF DIVALENT TIN SALTS OF ALIPHATIC MONO- AND DICARBOXYLIC ACIDS CONTAINING UP TO 54 CARBON ATOMS. 